Power tools have been available for many years for a variety of different applications including cleaning or polishing. Automated cleaning devices such as floor polishers, pot scrubbers, facial massagers, fingernail polishers and electric toothbrushes utilize a rapidly moving brush-like device at the end of a motorized drive shaft. The drive shaft of these devices either spins continuously in one direction or oscillates back and forth, and the brush device moves with the drive shaft.
Originally, the brush members of such power tools were permanently affixed to the drive shaft. Eventually, brush attachments were devised so that, when the scrubbing surface of the attachment lost its abrasive qualities, the attachment could be inexpensively replaced instead of replacing the entire unit. However, these attachments did not contain any independently moving parts, and the brush movement was limited to the rotational or alternating movement of the drive shaft.
U.S Pat. No. 4,156,620 discloses an apparatus for cleaning teeth wherein the brush portion of the apparatus contains a number of tufts which independently rotate and counter-rotate in response to the axial movement of a single drive shaft. This unusual brush movement has been shown to be successful in the prevention of cavities and peridontal problems caused by bacterial plaque.
U.S. patent application Ser. No. 743,100 describes a related cleansing apparatus which can be used for various cleaning applications including use by the dental patient in the home as a plaque-removing device. This apparatus is battery operated and sits in a recharging base until used.
The automatic cleaning device of U.S. Pat. No. 4,156,620 and U.S. patent application Ser. No. 743,100 is constructed as a one-piece unit. Therefore, if different brushes or replacement brushes are desired, the consumer will be forced to purchase an entire unit for each new brush or replace the tufts one at a time; and, if the device is used as a home plaque-removal instrument, separate units will be required by each user in any particular household.
Providing the described automatic cleaning device as a two-piece unit with a separate brush-containing head mechanism and a power-driven base presents special problems. Unlike conventional power tools, the brush portion of the above-described automatic cleaning device contains moving parts. Therefore, a simple, snap-on, brush-containing head member would be unable to translate the movements of the power drive contained within the base to the movable brushes contained within the head. Thus there is a need for a connection that can securely attach the powered drive shaft within the base to a reciprocating brush driving means within the brush-containing head.